Amazon.com: Epic IT Service - Geforce GT 640 for Mac Version, with 1GB GDDR5, PCI Express Gen 3.0, DVI-I DL, HDMI 2.0, DisplayPort 1.2, DirectX 12 (Boot Camp) Light Performance Board - OEM : Video Games
Galaxy GeForce GT 640 (NVIDIA) 1GB Video Card Review + Benchmarks! | The ChannelPro Network
Amazon.com: Epic IT Service - Geforce GT 640 for Mac Version, with 1GB GDDR5, PCI Express Gen 3.0, DVI-I DL, HDMI 2.0, DisplayPort 1.2, DirectX 12 (Boot Camp) Light Performance Board - OEM : Video Games
NVIDIA GeForce GT 640M - NotebookCheck.net Tech
Used - Very Good: ASUS GeForce GT 640 GT640-DCSL-2GD3 Video Card - Newegg.com